Genesis 17:19-22

19And 1God said, Sarah thy wife shall indeed bear thee a son; and thou shalt call his name Isaac; and I will establish my covenant with him, for an everlasting covenant for his seed after him.

20And for Ishmael I have heard thee: behold, I will bless him, and will make him fruitful, and will very greatly multiply him; twelve princes shall he beget, and I will make him a great nation.

21But my covenant will I establish with Isaac, whom Sarah shall bear to thee at this appointed time in the next year.

22And he left off talking with him; and 2God went up from Abraham.